1. Field of the Invention
The present disclosure relates to a gate system, and more particularly, to a gate system that has a radio frequency identification (RFID) system of an ultra high frequency band arranged on two gate frames and detects a tag passing between the two gate frames.
2. Description of the Related Art
Generally, a gate system is widely used in an electronic article surveillance system and a burglar detection system at a library.
The gate system commonly includes two gate frames that are vertically arranged at an entrance and an RFID system in the two gate frames.
The RFID system has antenna units arranged on the two gate frames and a reader, the two gate frames each having an antenna unit and the antenna units facing each other.
The gate system enables the reader to periodically apply a predetermined frequency signal to the antenna unit such that the antenna unit generates electromagnetic wave.
When a tag attached to an article passes between the two gate frames, the tag receives the electromagnetic wave generated in the antenna unit where the wave is activated, and transmits prestored information, that is, information on the article.
The antenna unit receives the certain information transmitted by the tag and provides the information for the reader. Further, the reader reads out the information input from the tag through the antenna unit and obtains the information on the article.
Further, recently, the gate system includes a monitoring camera, thereby increasing a tag recognition function. For example, the gate frame includes a monitoring camera arranged therein so that the monitoring camera takes a picture of a passing article, that is, the article attached to a tag. At this time, when an unrecognized tag has passed between the gate frames, the gate system implements a function to update data.
The RFID system mounted in the gate system uses a high frequency (HF) band. Since the RFID system that uses the HF band has a short recognition distance, it can precisely recognize only information on a tag of an article passing between the gate frames and cannot obtain information on tags of articles that are positioned nearby and have not passed between gate frames, so that the gate system operates normally.
Recently, the RFID system included in the gate system uses an ultra high frequency (UHF) band signal.
When the RFID system uses the UHF band signal, a tag recognition distance becomes about 5 cm, so errors often occur where the RFID system recognizes tag information of an article adjacently positioned to the gate frame that has not passed between the gate frames and tag information of an article that has passed between the gate frames.